Pregnancy is calculated based on the date of your last menstrual period. Four weeks have passed since your last menstruation. If you have missed your period, you might want to take a home pregnancy test to confirm whether or not you are pregnant.
If your test is negative but your period has not begun, wait another week and then test again. It can sometimes take 2 to 3 weeks after a missed period for some women to have a detectable level of pregnancy hormone.
Pregnancy lasts approximately 40 weeks. You are now 4 weeks pregnant and your embryo is approximately 2 weeks old.
If you have a positive pregnancy test and have not already done so, call your doctor to schedule your first prenatal visit. Don’t be surprised if your first checkup isn’t for another month or more. It is common for your first doctor’s visit to be at around 8 weeks.
What is Happening Inside Your Body?
You may begin to experience some early pregnancy symptoms at this point. Many of these symptoms feel the same as those you experience before your period. They can include headaches, backache, breast tenderness, fatigue and nausea.
You won’t have gained any weight at this point and your pregnancy won’t show yet.
How Big is Your Baby?
How is Your Baby Developing?
The embryo is beginning to develop into three distinct layers. These layers are called the ectoderm, mesoderm, and endoderm.
The ectoderm is the top. It will become the outer layers of the skin, hair, nails, nipples, tooth enamel, the lenses of the eyes, and most of the nervous system.
The middle is the mesoderm. It will form into muscle, bone, connective tissue, heart, blood vessels, and reproductive organs.
The bottom is the endoderm. This layer will form the lungs, digestive organs, liver, pancreas, stomach, spleen, bowl, urinary tract and bladder.
An amniotic sac has now developed, surrounding and cushioning your baby, as has a yolk sac, which will help nourish your baby.
The placenta is beginning to form and produce hCG and other hormones.
What Does a Fetus Look Like at 4 weeks?
The best way to see what is going on at 4 weeks. This is actually 14 days after after conception. Click here to watch video.
Tips for a Healthy Pregnancy
Be sure that you are taking a prenatal vitamin. Eat lots of healthy food, drink plenty of water, exercise and get adequate rest.
Be careful about what you put into your body. Avoid alcohol, recreational drugs, smoking, second hand smoke, and check with your doctor before taking any over the counter or prescription medications or herbal medicines. Remember that your baby will be taking into its body whatever your put into yours.